Somewhat disappointingly (and different to my understanding of "easily" and "from a smartphone") followed further down by:
In order to make it working, you need a computer with a Debian-like operating system and two Wi-Fi interfaces. The best choice is to use a Raspberry Pi (3+) with a Wi-Fi dongle and a small touch screen...
"The idea of TinyCheck came to me in a meeting about stalkerware with a French women's shelter. During this meeting we talked about how to easily detect easily stalkerware without installing very technical apps nor doing forensic analysis on them. The initial concept was to develop a tiny kiosk device based on Raspberry Pi which can be used by non-tech people to test their smartphones against malicious communications issued by stalkerware or any spyware."
I think it's a great idea. I'm going to check in with a friend who has to deal with stalker ware-infected phones at a womens shelter she volunteers at to see if they'd like me to build/send them one.
It would definitely be nice to see it deployable in a quick and easy way for less tech savvy users.
Dual wifi makes for easier installation/operation in a lot of situations though, so I think its a good "default config". If there's already a wifi network people can use, hooking one wifi chipset to that then connecting the phones under test to an access point broadcast by the other - is easier than expecting there to be a live ethernet port and someone at a womens shelter-style-place having access to it and skills to use it.
This should be fairly simple too so long as there's no arbitrary restriction on requiring wlan devices preventing you from using WiFi+Ethernet rather than Wifi+Wifi.
The other interface is to connect the TinyCheck box to the internet, so it could well be a wired connection.
I suspect that if your WiFi device can support AP and client mode simultaneously it should work just as well.